This paper reports on a project that aims to create an Annotation standard for Non-Manual elements in visual communication (ANM). Specifically, we describe two phases of the project: the proof-of-concept phase and the prototype phase. For both these phases, we passed through the same cycle of three steps: (i) drafting annotation guidelines, (ii) having two annotators annotate a test data set using these guidelines, and (iii) evaluating the test annotations for inter-annotator agreement. The outcome of the first iteration (i.e., the proof-of-concept phase) was a set of recommendations that informed the development of the prototype guidelines. The present paper discusses all steps of the two phases; however, since we have previously reported on our work in the proof-of-concept phase of the project elsewhere, the main focus is on the prototype phase. Finally, the paper goes into the remaining two major objectives of the project: creating an open-access online platform hosting the annotation guidelines, and setting up a collaborative network of research teams responsible for further developing and maintaining the guidelines.